Downing Street has announced that the UK will help deliver weapons to the Kurds - so long as they are supplied by other countries - to fight back against the murderous fanatics of the Islamic State.

But as David Cameron returned from his holiday in Portugal this morning to chair today's meeting of the Cabinet crisis committee Cobra, he was still resisting pressure for more direct action to avert disaster in Iraq.

Speaking after the meeting, Cameron said "Britain will play a role" in the international mission to rescue the Yazidis, but the BBC said "the focus remained on humanitarian supplies, although Chinook [helicopters] could also be used to airlift refugees to safety".

Cameron has lost the support of senior figures in his own party over his refusal to recall Parliament and seek approval for the UK to join the US in air strikes against the Islamic State.

Liam Fox, the former Defence Secretary, attacked the "catastrophic complacency" of western governments, including our own. He is the most senior figure to demand that Britain join the US in carrying out bombing raids against the Sunni fanatics, and he acts as a rallying point for opposition to Cameron after refusing a junior post in the Prime Minister's recent reshuffle.

Tim Collins, the former British Army colonel famed for his inspirational speech on the eve of the 2003 Iraq War, said that Britain’s politicians had “left for lunch” as he urged Cameron to recall Parliament to debate the crisis.

Interestingly, both Fox and Collins appear to reflect growing public opinion in favour of military intervention.

Cameron was running ahead of public opinion when MPs decisively rejected his demand last year for approval for UK military action against the Assad regime in Syria. But a new ComRes poll for ITV News suggests he is now running behind public opinion regarding the Iraq crisis.

ComRes found that 45 per cent of Britons approve of the RAF taking part in air strikes – while 37 per cent disapprove. Last August 50 per cent of the country was opposed to missile strikes on Syria with just 25 per cent in support.

So far, Cobra, chaired by Foreign Secretary Philip Hammond in Cameron's absence, has restricted UK action to humanitarian aid. Hercules transport planes have made air drops of food to the Yazidi refugees suffering searing 33C temperatures on the bare plateau of Mount Sinjar.

RAF Tornado jets have accompanied them on "surveillance" flights but appear to be under orders not to fire, unless they are fired on.

However, Cobra is cautiously edging towards deeper involvement. A Downing Street statement released yesterday said the UK government had agreed to transport "critical military re-supplies" provided by other countries to Kurdish forces fighting IS.

France said today that it will start arming Kurdish forces this afternoon.

If Parliament is ever recalled, MPs would regard that decision as pathetically hypocritical. It means the UK is happy to supply weapons from other countries - presumably the US – but refuses to sanction supplying its own weapons to the embattled Kurds.

The Kurds have proved the only effective force in the region to stand up to IS, although they are outgunned by IS fighters who are using US-supplied heavy weapons - including tanks and missiles - they seized when the Iraqi army ran away.

Meanwhile, Channel 4 News has been reporting nightly on the humanitarian mission by four Iraqi helicopters to deliver food and water to the stranded Yazidis, and take as many of them off Mount Sinjar as they can manage.

Many MPs are certain to regard C4's images of the Yazidis, begging to be allowed onto the dangerously overcrowded helicopters, as shaming for the UK.

C4's Jonathan Rugman said the Iraqis desperately need more helicopters to airlift the Yazidis to safety if they are not to die in their hundreds. And that was before one of the four helicopters crash-landed yesterday, killing the pilot, and they're now down to three.